I read some items about aquaculture but only about breeding fish. But why not growing seaweed? It grows only by sunlight and a bit fertilizer. Some kinds of seaweed contain oil, which can be used for energy. The seaweed binds CO2, so perhaps one could even sell greenhouse gas emission rights. Manure from fish farms can be used as fertilizer, rather than dumping it in the ocean.

Floating kelp platforms were built in the late seventies by Dr. Wheeler J. North and his assistants as a potential source of energy and food. Unfortunately, the submerged platforms were destroyed in storms. I attended a talk by Dr. North and was quite inspired by the idea. The oil glut in the 80’s led to an end in funding for the research. link: http://www.oceansatlas.org/servlet/CDSServlet?status=ND0zMTk5JjY9ZW4mMzM9KiYzNz1rb3M~

Despite the misconceptions that plagued the Ocean Food and Energy Farm, Wilcox’s projection of 2% efficiency in conversion of sunlight to energy was not realistic. As mentioned above, NMI’s near-shore growth data demonstrated a 1% efficiency (conservative estimate), a number that confirms the viability of marine biomass as a source of energy. NMI also demonstrated that Macrocystis has an exceedingly high rate of biomass production (fifteen dry ash-free tons per acre per year), and that the plants can withstand quarterly harvests where up to half of the biomass is removed. Furthermore, survival of plants following repeated harvesting showed that substantial yields were possible without changing the standing crop.

Review of the marine biomass program provides valuable lessons for future development of marine farming. Of the many difficulties that plagued initial efforts to farm the sea, one in particular, stands out—the lack of communication between engineering and biological communities. The project began with the assumption that marine farming would not be technically difficult. Wilcox’s statement that “It’s not high technology… we’re just talking about plain old plants growing,” illustrates this lack of understanding. Ten years later, after the work of two contractors and several major experimental farming efforts, there was still no yield data for farmed Macrocystis. Plants were entangled with the farm structures, consumed by fish, infected, or dislodged and destroyed by storms. By 1980, it was apparent that building a “false bottom” for kelp plants in the open-ocean was not a “low-tech” task. Attempts to protect the structures with a fabric current shield (ripped away) also met with failure. While marine engineers learned from the QAM and grid experiments, biologists were unable to obtain any significant growth data from the experiments.

Many of the problems associated with marine farming were due to constraints on the overall Marine Biomass Program. In particular, Wilcox’s original concept required an enormous amount of marine biomass, near-shore work was not deemed to be worthwhile. This resulted in an approach that required both engineers and biologists to “walk before they could crawl,” an obstacle that contributed to the lack of data generated by the early open-ocean experiments. Without this crucial growth data, there was no way of testing Wilcox’s theory about the biomass potential of marine farming. NMI produced these data by planting and harvesting a near-shore marine farm. Current efforts to revive the program should take particular care not to overlook the experience of earlier investigators. Marine plant specialists must be involved from the very beginning and should play an active role in the design of farming structures. From an engineering perspective, the grid and QAM experiments were somewhat useful in that they highlighted the many problems encountered in placing artificial substrates in deep water. However, the lack of significant growth data demonstrated that the success of marine farming did not hinge solely upon the ability to anchor the structures in the ocean. In particular, engineers needed to account for the hydrodynamic requirements of the marine plants that they were attempting to grow. Future project managers must place the plants first in order to succeed in the production of marine biomass.

Growing in the Sargasso would be easier in nice, warm, water, and doesn’t require a submerged structure. Kelp grows in cold water. General Electric’s research in biomass to methane conversion would be useful to review since it would apply to any type of seaweed harvested for energy.

Hi Conrad, that’s exactly what I’m doing over here in Singapore. We’re a polyculture farm that grows several species of macro-algae from the waste of our predatory fish to feed our prawns, lobsters, herbivorous fish and abalone.

In fact, ALL species of “seaweed” contain oil. You see, “oily fish” like sardines get their oil from the microscopic algae that they eat, they don’t actually produce it themselves. And larger ones like Tuna and Marlin get their oils from sardines.

What some associates over at James Cook University have done is grow massive amounts micro-algae from the CO2 generated by a fossil fuel power station, then separate the algae into carbohydrates and oils for sale.

What some associates over at James Cook University have done is grow massive amounts micro-algae from the CO2 generated by a fossil fuel power station, then separate the algae into carbohydrates and oils for sale.

King Shannon of the Constitutional Monarchy of Logos.

Is this fresh or salt water algae? So far I’ve only seen fresh water algae studied for biodiesel. It would be great if there are species of hi yielding algae for oil which grow in seawater. Krill oil is now being sold as a health supplement.

They’ve done studies on both. As for a species that grows in seawater… most species of unicellular algae should be good candidates. You just need to adapt freshwater CO2 diffusers and find a way to prevent the pH from crashing. Or just pump large amounts of regular air through a ceramic diffuser…

You’d need a large centrifuge to gather it all at the end of the cycle.